Method and System for Discovering a Power Source on a Peripheral Bus

1. A power source comprising: a power line; a ground line; available power circuitry operatively coupled to the power line and the ground line, wherein the available power circuitry is configured to provide a first voltage on a first output and a second voltage on a second output, the first and second voltages indicating a level of power available from the power source; and a connector including a power pin coupled to the power line, a ground pin coupled to the ground line, a first digital data pin coupled to the first output of the available power circuitry, and a second digital data pin coupled to the second output of the available power circuitry, wherein when the connector is coupled to a peripheral bus connector of an electronic device: the power line is operable to provide power to a peripheral bus connector of an electronic device via the power pin, and the first and second digital data pins are operable to provide the first and second voltages to respective digital data input pins of the peripheral bus connector of the electronic device, wherein the sign of the difference between the first voltage and the second voltage indicates whether the power source is a power adapter that receives AC power or a battery pack.

2. The power source of claim 1 , wherein the connector is a USB connector.

3. A power source comprising: a power line; a ground line; available power circuitry operatively coupled to the power line and the ground line, wherein the available power circuitry is configured to provide a first voltage on a first output and a second voltage on a second output, the first and second voltages indicating a level of power available from the power source; and a connector including a power pin coupled to the power line, a ground pin coupled to the ground line, a first digital data pin coupled to the first output of the available power circuitry, and a second digital data pin coupled to the second output of the available power circuitry, wherein when the connector is coupled to a peripheral bus connector of an electronic device: the power line is operable to provide power to a peripheral bus connector of an electronic device via the power pin, and the first and second digital data pins are operable to provide the first and second voltages to respective digital data input pins of the peripheral bus connector of the electronic device, wherein the first and second voltage are both higher than the voltage used by the electronic device to determine whether a data value is high or low.

4. The power source of claim 3 , wherein the connector is a USB connector.

5. A power source comprising: a power line; a ground line; available power circuitry operatively coupled to the power line and the ground line, wherein the available power circuitry is configured to provide a first voltage on a first output and a second voltage on a second output, the first and second voltages indicating a level of power available from the power source; and a connector including a power pin coupled to the power line, a ground pin coupled to the ground line, a first digital data pin coupled to the first output of the available power circuitry, and a second digital data pin coupled to the second output of the available power circuitry, wherein when the connector is coupled to a peripheral bus connector of an electronic device: the power line is operable to provide power to a peripheral bus connector of an electronic device via the power pin, and the first and second digital data pins are operable to provide the first and second voltages to respective digital data input pins of the peripheral bus connector of the electronic device, wherein the available power circuitry includes a voltage divider between the power line and the ground line, the voltage divider including a first resistance coupled between the power line and the first output, a second resistance coupled between the first output and the second output, and a third resistance coupled between the second output and a ground line.

6. The power source of claim 5 , wherein the connector is a USB connector.

7. A power source comprising: a power line; a ground line; available power circuitry operatively coupled to the power line and the ground line, wherein the available power circuitry is configured to provide a first voltage on a first output and a second voltage on a second output, the first and second voltages indicating a level of power available from the power source; and a connector including a power pin coupled to the power line, a ground pin coupled to the ground line, a first digital data pin coupled to the first output of the available power circuitry, and a second digital data pin coupled to the second output of the available power circuitry, wherein when the connector is coupled to a peripheral bus connector of an electronic device: the power line is operable to provide power to a peripheral bus connector of an electronic device via the power pin, and the first and second digital data pins are operable to provide the first and second voltages to respective digital data input pins of the peripheral bus connector of the electronic device, wherein the available power circuitry includes a voltage divider between the power line and the ground line, the voltage divider comprising at least three resistive elements, wherein the first voltage is provided on a first node between a first pair of resistive elements and the second voltage is provided on a second node between a second pair of resistive elements, wherein the first pair is different than the second pair.

8. The power source of claim 7 , wherein the connector is a USB connector.

9. The power source of claim 7 , wherein the power line is directly connected to a resistive element of the first pair of resistive elements.

10. The power source of claim 7 , wherein the ground line is directly connected to a resistive element of the second different pair of resistive elements.

11. A power source comprising: a power line; a ground line; available power circuitry operatively coupled to the power line and the ground line, wherein the available power circuitry is configured to provide a first voltage on a first output and a second voltage on a second output, the first and second voltages indicating a level of power available from the power source; and a connector including a power pin coupled to the power line, a ground pin coupled to the ground line, a first digital data pin coupled to the first output of the available power circuitry, and a second digital data pin coupled to the second output of the available power circuitry, wherein when the connector is coupled to a peripheral bus connector of an electronic device: the power line is operable to provide power to a peripheral bus connector of an electronic device via the power pin, and the first and second digital data pins are operable to provide the first and second voltages to respective digital data input pins of the peripheral bus connector of the electronic device, wherein the available power circuitry includes at least two voltage dividers, each comprising at least two resistive elements coupled between the power line and the ground line, wherein the first voltage is provided on a first node between a first pair of resistive elements of a first voltage divider, and wherein the second voltage is provided on a second node between a second pair of resistive elements of a second voltage divider.

12. The power source of claim 11 , wherein the connector is a USB connector.

13. A method of providing power to a peripheral bus connector of an electronic device from a first connector of a power source, the method comprising: providing power to the first connector of the power source using a power line and a ground line, wherein a power pin of the first connector is coupled to the power line and a ground pin of the first connector is connected to the ground line; determining, with available power circuitry, at least two indicator voltages based on voltages on the power line and the ground line, the indicator voltages indicating a level of power available from the power source; and providing respective indicator voltages from the available power circuitry to first and second digital data pins of the first connector; when the first connector is coupled with the peripheral bus connector of the electronic device, providing the respective indicator voltages from the first and second digital data pins of the first connector to respective digital data input pins of the peripheral bus connector of the electronic device, thereby providing a level of power available to the electronic device from the power source, wherein the sign of the difference between the indicator voltages at the first and second digital data pins indicates whether the power source is a power adapter that receives AC power or a battery pack.

14. A method of providing power to a peripheral bus connector of an electronic device from a first connector of a power source, the method comprising: providing power to the first connector of the power source using a power line and a ground line, wherein a power pin of the first connector is coupled to the power line and a ground pin of the first connector is connected to the ground line; determining, with available power circuitry, at least two indicator voltages based on voltages on the power line and the ground line, the indicator voltages indicating a level of power available from the power source; and providing respective indicator voltages from the available power circuitry to first and second digital data pins of the first connector; when the first connector is coupled with the peripheral bus connector of the electronic device, providing the respective indicator voltages from the first and second digital data pins of the first connector to respective digital data input pins of the peripheral bus connector of the electronic device, thereby providing a level of power available to the electronic device from the power source, wherein the indicator voltage levels are all greater than a minimum level voltage that is used to determine whether a voltage at a peripheral bus data line associated with the peripheral bus connector of the electronic device is “High” or “Low.”

15. A method of providing power to a peripheral bus connector of an electronic device from a first connector of a power source, the method comprising: providing power to the first connector of the power source using a power line and a ground line, wherein a power pin of the first connector is coupled to the power line and a ground pin of the first connector is connected to the ground line; determining, with available power circuitry, at least two indicator voltages based on voltages on the power line and the ground line, the indicator voltages indicating a level of power available from the power source; and providing respective indicator voltages from the available power circuitry to first and second digital data pins of the first connector; when the first connector is coupled with the peripheral bus connector of the electronic device, providing the respective indicator voltages from the first and second digital data pins of the first connector to respective digital data input pins of the peripheral bus connector of the electronic device, thereby providing a level of power available to the electronic device from the power source, wherein determining at least two indicator voltages based on the voltages on the power line and the ground line includes: receiving power from the power line at a voltage divider, the voltage divider comprising at least three resistive elements, wherein the first digital data pin is coupled to a first node between a first pair of resistive elements and the second digital data pin is coupled to a second node between a second pair of resistive elements, wherein the first pair is different than the second pair.

16. The method of claim 15 , wherein the first connector is a USB connector.

17. The method of claim 15 , wherein the power line is directly connected to a resistive element of the first pair of resistive elements.

18. The method of claim 15 , wherein the ground line is directly connected to a resistive element of the second different pair of resistive elements.

19. A method of providing power to a peripheral bus connector of an electronic device from a first connector of a power source, the method comprising: providing power to the first connector of the power source using a power line and a ground line, wherein a power pin of the first connector is coupled to the power line and a ground pin of the first connector is connected to the ground line; determining, with available power circuitry, at least two indicator voltages based on voltages on the power line and the ground line, the indicator voltages indicating a level of power available from the power source; and providing respective indicator voltages from the available power circuitry to first and second digital data pins of the first connector; when the first connector is coupled with the peripheral bus connector of the electronic device, providing the respective indicator voltages from the first and second digital data pins of the first connector to respective digital data input pins of the peripheral bus connector of the electronic device, thereby providing a level of power available to the electronic device from the power source, wherein determining at least two indicator voltages based on the voltages on the power line and the ground line includes: receiving power from the power line at a plurality of voltage dividers, each comprising at least two resistive elements, wherein the first digital data pin is coupled to a first node between a first pair of resistive elements of a first voltage divider, and wherein the second digital data pin is coupled to a second node between a second pair of resistive elements of a second voltage divider.

20. The method of claim 19 , wherein the first connector is a USB connector.